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PubMed1997

The relationship between umbilical artery Doppler findings, fetal biophysical score and placental inflammation in cases of premature rupture of membranes.

BACKGROUND: To assess the relationship between placental inflammation, umbilical artery Doppler waveforms and fetal biophysical profile score, umbilical artery Doppler studies and fetal biophysical evaluations were performed in 24 preterm pregnants with premature rupture of membranes (PPROM). SUBJECTS: After delivery, the placentas were microscopically examined and two subgroups were formed including noninflamed or inflamed placentas. RESULTS: In the first group, which includes 14 cases with no histological signs of placental inflammation, we found increased systolic/diastolic ratio only in one patient, whereas in the second group including ten cases with microscopically proven inflammation, nine were found to have increased systolic/diastolic ratios (p < 0.05). Mean systolic/diastolic ratio in the first and the second groups were 2.74 +/- 0.18 and 4.64 +/- 0.93 respectively (p < 0.001). Mean biophysical profile score was 9 +/- 1.04 in the first group and 7 +/- 1.05 in the second group (p < 0.001). CONCLUSION: Abnormal biophysical profile scores along with increased arterial systolic/diastolic ratios have been shown to be the markers of impending clinical infection.

Adolescent↗
PubMed1999

The effect of betamethasone on fetal biophysical activities and Doppler velocimetry of umbilical and middle cerebral arteries.

OBJECTIVE: Preliminary reports suggest that antenatal steroid administration may confound the assessment of fetal well-being by suppressing biophysical activities, consequently drug-induced effects could prompt unwarranted delivery of premature fetuses. The purpose of this study was to examine the effect of antenatal betamethasone administration on fetal biophysical activities and Doppler flow indices of the umbilical and middle cerebral circulation. METHODS: Forty women at risk of premature delivery between 27-32 weeks gestation (mean 30.2 weeks) received two consecutive doses of intramuscular betamethasone, 24 hours apart. Ultrasonographic observations of fetal behavior for 30 minute periods and Doppler examination of the umbilical and cerebral arteries were performed prior to (0 hours), 48 hours after, and 96 hours after administration of the first dose. To account for fetal circadian rhythms and maternal prandial status, all examinations were carefully timed and performed between 1-4 pm. Analysis of Variance, chi-square test and Fisher's Exact test were used for statistical analysis, as appropriate. RESULTS: Nine patients were excluded from analysis due to delivery prior to completion of all examinations. Number of breathing episodes as well as total breathing time at 48 hours decreased by 83.0% (p<0.01) and 90.4% (p<0.01), respectively, at 48 hours in comparison to baseline. Fetal limb and trunk movements decreased by 53.2% (p<0.01) and 48.6% (p<0.01), respectively. Amniotic fluid volume and fetal tone were normal in all patients. At 48 hours, 14 of 31 fetuses and 4 of 31 fetuses had a biophysical profile score of 6/8 and 4/8, respectively, in comparison to 0 of 31 and 0 of 31 at 0 hours (p<0.05 and p<0.001, respectively). All parameters returned to baseline values at 96 h. Pulsatility indices of umbilical and middle cerebral arteries remained unchanged at 48 hours and 96 hours (p=NS). CONCLUSIONS: Betamethasone induces a profound, albeit transient, suppression of fetal breathing, limb and trunk movements, resulting in decreased biophysical profile scores. Awareness of this drug-induced effect might prevent unnecessary iatrogenic delivery of preterm fetuses.

Adult↗
PubMed2005

Bone development: interaction of molecular components and biophysical forces.

A deeper understanding of skeletal development comes from knowledge of the molecular components, cell and tissue structure, and biophysical and vascular mechanisms underlying physiologic function. Endochondral and intramembranous bone formation mechanisms are active during long bone synthesis. Most endochondral growth in length occurs at the physes by the coordinated actions of cell proliferation, matrix synthesis, and chondrocyte hypertrophy. Several intrinsic molecules act to modulate physeal structure and function whereas extrinsic molecules, such as hormones, provide systemic regulation of growth. Biophysical forces develop intrinsically within the growing bone, serving to enlarge it in three dimensions, while extrinsic forces resist and channel expansion into normal recognizable and functional forms. Newer imaging modalities, such as magnetic resonance imaging, are highly effective in assessing epiphyseal vascularity and differentiating fibrous, cartilaginous, mineralized and osseous tissues in prenatal and postnatal developing bone. This study illustrates the interplay between the molecular and biophysical aspects of normal bone growth, shows ways in which altered development leads to abnormal structures, and provides examples where biologic and biophysical interventions can affect bone development in favorable ways.

Biomechanical Phenomena↗
PubMed2005

[Advances of studies on the biophysical characteristics of channels and acupoints].

OBJECTIVE: To summarize recent studies on the biophysical characteristics of meridians and acupoints, so as to provide a basis and thinking for scientific studies. METHODS: Twenty-nine papers about biophysical characteristics of meridians and acupoints were reviewed from studies of electricity, heat, sound, light, magnetic and radionuclide. RESULTS: The biophysical characteristics of meridians and acupoints have been proved in different domains, and meridians and acupoints objectively exist. CONCLUSION: Scientific studies on the biophysical characteristics of meridians and acupoints have vast vistas.

Acupuncture Points↗
PubMed2006

In vitro biophysical strain model for understanding mechanisms of osteopathic manipulative treatment.

CONTEXT: Normal physiologic movement, pathologic conditions, and osteopathic manipulative treatment (OMT) are believed to produce effects on the shape and proliferation of human fibroblasts. Studies of biophysically strained fibroblasts would be useful in producing a model of the cellular mechanisms underlying OMT. OBJECTIVE: To investigate the effects of acyclic in vitro biophysical strain on normal human dermal fibroblasts and observe potential changes in cellular shape and proliferation, as well as potential changes in cellular production of nitric oxide, interleukin (IL) 1beta, and IL-6. DESIGN AND METHODS: Randomized controlled trial. Human fibroblasts were subjected in vitro to control conditions (no strain) or biophysical strain of various magnitudes (10%-30% beyond resting length) and durations (12-72 hours). After control or strain stimuli, fibroblasts were analyzed for potential changes in cell shape, proliferative capacity, nitric oxide secretion, and cytokine (IL-1beta, IL-6) secretion. RESULTS: Low strain magnitudes (<20%) induced mild cellular rounding and pseudopodia truncation. High strain magnitudes (>20%) decreased overall cell viability and the mitogenic response, and induced cell membrane decomposition and pseudopodia loss. No basal or strain-induced secretion of IL-1beta was observed. Interleukin 6 concentrations increased two-fold, while nitric oxide levels increased three-fold, in cells strained at 10% magnitude for 72 hours (P<.05). CONCLUSION: Human fibroblasts respond to in vitro strain by secreting inflammatory cytokines, undergoing hyperplasia, and altering cell shape and alignment. The in vitro biophysical strain model developed by the authors is useful for simulating a variety of injuries, determining in vivo mediators of somatic dysfunction, and investigating the underlying mechanisms of OMT.

Biomechanical Phenomena↗
PubMed1991

The effect of magnesium sulfate on the biophysical profile of normal term fetuses.

Forty term pregnant women with singleton breech gestations admitted for external cephalic version underwent biophysical profile testing before any fluid infusion or medication. After magnesium sulfate had been infused for contraction prophylaxis, the maternal serum magnesium level was measured and a second biophysical profile was performed. The mean (+/- SD) serum magnesium was 5.1 +/- 1.0 mg/dL. The biophysical profile score decreased significantly, reflecting a decrease in fetal breathing activity. In patients with therapeutic maternal serum magnesium levels, loss of any component of the biophysical profile other than respiration cannot be attributed to the elevation in magnesium concentration.

Adult↗
PubMed1989

Use of the fetal biophysical profile in severe oligohydramnios after preterm premature rupture of the membranes.

A protocol of expectant management using daily fetal biophysical assessment was applied to 23 consecutive women with severe oligohydramnios after preterm premature rupture of the membranes. A persistently low biophysical score (less than or equal to 6 on two examinations two hours apart) in the presence of a nonreactive nonstress test and absence of fetal breathing was used as an indication for delivery. The pregnancy outcome in this group was compared to that in a historic control group managed similarly except that an abnormal biophysical assessment was not an indication for delivery. The results suggest that the management of women with severe oligohydramnios after preterm premature rupture of the membranes with daily fetal biophysical profiles decreases the incidence of low five-minute Apgar scores as well as that of maternal and neonatal infection.

Amniotic Fluid↗
PubMed1986

Metastatic pheochromocytoma in pregnancy and fetal biophysical assessment after maternal administration of alpha-adrenergic, beta-adrenergic, and dopamine antagonists.

Metastatic pheochromocytoma, a rare complication of pregnancy, was managed from 30 weeks' gestation until delivery three weeks later with a combination of alpha-adrenergic blockade (Minipres) beta-adrenergic blockade (Timolol), and dopamine synthesis inhibition (Demser). The biophysical parameters of fetal heart rate (FHR) baseline, variability, and reactivity, as well as fetal breathing movements, body movements, tone, and amniotic fluid volume were followed sequentially during this period. A 1450-g growth-retarded infant, who subsequently did well, was delivered by cesarean section; the mother received combined surgical and medical therapy for her metastatic disease in the postpartum period. The initial fetal biophysical alteration observed was a reduction in mean FHR baseline rate; further biophysical test abnormalities appeared only after overt fetal compromise was evident. Sequential multiple parameter biophysical testing in such circumstances appears to be a valid and valuable approach to antepartum management.

Adult↗
PubMed1985

A prospective trial of the fetal biophysical profile versus the nonstress test in the management of high-risk pregnancies.

A randomized prospective trial study was developed to determine the diagnostic value of the fetal biophysical profile in relationship to the nonstress test. The diagnostic values of these tests were assessed in terms of the incidence of abnormal outcome. In addition comparisons between the positive and negative predictive values of each of these tests as well as the sensitivity and specificities of the test were reviewed. A total of 652 patients were entered into the study and a total of 1628 tests were performed. Of the group 279 pregnancies were managed by a biophysical profile protocol and 373 by the nonstress test protocol. Results of this study suggest that except for the negative predictive value in the sensitivities in the outcome parameters of low 5-minute Apgar scores the diagnostic values for all outcome parameters were consistently higher in the fetal biophysical profile as opposed to the nonstress test group. While higher, only two of the values, positive predictive value of overall abnormal outcome and negative predictive value of small for gestational age infants, were statistically significant. While this general trend suggests that the biophysical profile is more predictive in diagnosing fetal condition than the nonstress test, because statistical significance was not reached in all parameters further study is warranted.

Amniotic Fluid↗
PubMed1983

Further experience with the fetal biophysical profile.

At Los Angeles County/University of Southern California Medical Center, the authors performed biophysical profile testing on 186 fetuses within one week of delivery. One component of the biophysical profile is the nonstress test. The other four components are fetal parameters observed with real-time ultrasonography: fetal breathing movements, fetal movements, fetal tone, and amniotic fluid volume. Clinicians managed the patients on the basis of the nonstress test result, and the authors did not report the other biophysical profile results. Measures of outcome included perinatal mortality, fetal distress in labor, low five-minute Apgar score, and birth weight small for gestational age. Results indicate that fetal biophysical parameters other than the response, or lack of response, of the fetal heart rate to fetal movements may have predictive value in assessing the state of fetal health. In the future, real-time ultrasonography may prove to be a reliable adjunct to antepartum electronic fetal heart rate monitoring.

Amniotic Fluid↗
PubMed2006

Biophysical and structural characterization of polyethylenimine-mediated siRNA delivery in vitro.

PURPOSE: The goals of this study were as follows: 1) to evaluate the efficacy of different polyethylenimine (PEI) structures for siRNA delivery in a model system, and 2) to determine the biophysical and structural characteristics of PEI that relate to siRNA delivery. MATERIALS AND METHODS: Biophysical characterization (effective diameter and zeta potential), cytotoxicities, relative binding affinities and in vitro transfection efficiencies were determined using nano-complexes formed from PEI's of 800, 25,000, (both branched) and 22,000 (linear) molecular weights at varying N:P ratios and siRNA concentrations. The HR5-CL11 cell line stably expressing luciferase was used as a model system in vitro. RESULTS: Successful siRNA delivery was observed within a very narrow window of conditions, and only with the 25,000 branched PEI at an N:P ratio of 6:1 and 8:1 and with 200 nM siRNA. While the zeta potential and size of PEI:siRNA complexes correlated to transfection efficacy in some cases, complex stability may also affect transfection efficacy. CONCLUSIONS: The ability of PEI to transfer functionally active siRNA to cells in culture is surprisingly dependent on its biophysical and structural characteristics when compared to its relative success and ease of use for DNA delivery.

Biophysical Phenomena↗
PubMed2006

Biophysical characterization of S100A8 and S100A9 in the absence and presence of bivalent cations.

S100A8 and S100A9 are two proinflammatory molecules belonging to the S100 family of calcium-binding proteins. Common to all S100 proteins S100A8 and S100A9 form non-covalently associated complexes which have been shown to exhibit different functional properties. Besides dimerization, recent research is focused on the importance of higher oligomeric structures of S100 proteins induced by bivalent cations. While S100A8/S100A9-heterodimers are formed in the absence of calcium, tetramerization is strictly calcium-dependent. Heterodimer formation is not a simple process and our biophysical analyses (FRET, ESI-MS) demonstrate that simply mixing both subunits is not sufficient to induce complex formation. Steps of denaturation/renaturation are necessary for the recombinant complex to show identical biophysical properties as S100A8/S100A9 obtained from granulocytes. In addition to calcium both proteins are able to bind zinc with high affinity. Here we demonstrate for the first time by different biophysical methods (MALDI-MS, ESI-MS, fluorescence spectroscopy) that zinc-binding, like calcium, induces (S100A8/S100A9)(2)-tetramers. Using mass spectrometric investigations we demonstrate that zinc triggers the formation of (S100A8/S100A9)(2)-tetramers by zinc-specific binding sites rather than by interactions with calcium-specific EF-hands. The zinc-induced tetramer is structurally very similar to the calcium-induced tetramer. Thus, like calcium, zinc acts as a regulatory factor in S100A8/S100A9-dependent signaling pathways.

Biophysical Phenomena↗
PubMed2006

A biophysical approach to the optimisation of dendritic-tumour cell electrofusion.

Electrofusion of tumour and dendritic cells (DCs) is a promising approach for production of DC-based anti-tumour vaccines. Although human DCs are well characterised immunologically, little is known about their biophysical properties, including dielectric and osmotic parameters, both of which are essential for the development of efficient electrofusion protocols. In the present study, human DCs from the peripheral blood along with a tumour cell line used as a model fusion partner were examined by means of time-resolved cell volumetry and electrorotation. Based on the biophysical cell data, the electrofusion protocol could be rapidly optimised with respect to the sugar composition of the fusion medium, duration of hypotonic treatment, frequency range for stable cell alignment, and field strengths of breakdown pulses triggering membrane fusion. The hypotonic electrofusion consistently gave a tumour-DC hybrid rate of up to 19%, as determined by counting dually labelled fluorescent hybrids in a microscope. This fusion rate is nearly twice as high as that usually reported in the literature for isotonic media. The experimental findings and biophysical approach presented here are generally useful for the development of efficient electrofusion protocols, especially for rare and valuable human cells.

Biophysical Phenomena↗
PubMed2004

Estimation of neurophysiological parameters from the waking EEG using a biophysical model of brain dynamics.

This paper presents the results from using electroencephalographic (EEG) data to estimate the values of key neurophysiological parameters using a detailed biophysical model of brain activity. The model incorporates spatial and temporal aspects of cortical function including axonal transmission delays, synapto-dendritic rates, range-dependent connectivities, excitatory and inhibitory neural populations, and intrathalamic, intracortical, corticocortical and corticothalamic pathways. Parameter estimates were obtained by fitting the model's theoretical spectrum to EEG spectra from each of 100 healthy human subjects. Statistical analysis was used to infer significant parameter variations occurring between eyes-closed and eyes-open states, and a correlation matrix was used to investigate links between the parameter variations and traditional measures of quantitative EEG (qEEG). Accurate fits to all experimental spectra were observed, and both inter-subject and between-state variability were accounted for by the variance in the fitted biophysical parameters, which were in turn consistent with known independent experimental and theoretical estimates. These values thus provide physiological information regarding the state. transitions (eyes-closed vs. eyes-open) and phenomena including cortical idling and alpha desynchronization. The parameters are also consistent with traditional qEEG, but are more informative, since they provide links to underlying physiological processes. To our knowledge, this is the first study where a detailed biophysical model of the brain is used to estimate neurophysiological parameters underlying the transitions in a broad range (0.25-50 Hz) of EEG spectra obtained from a large set of human data.

Awareness↗
PubMed2006

Ultrasound-biophysics mechanisms.

Ultrasonic biophysics is the study of mechanisms responsible for how ultrasound and biological materials interact. Ultrasound-induced bioeffect or risk studies focus on issues related to the effects of ultrasound on biological materials. On the other hand, when biological materials affect the ultrasonic wave, this can be viewed as the basis for diagnostic ultrasound. Thus, an understanding of the interaction of ultrasound with tissue provides the scientific basis for image production and risk assessment. Relative to the bioeffect or risk studies, that is, the biophysical mechanisms by which ultrasound affects biological materials, ultrasound-induced bioeffects are generally separated into thermal and non-thermal mechanisms. Ultrasonic dosimetry is concerned with the quantitative determination of ultrasonic energy interaction with biological materials. Whenever ultrasonic energy is propagated into an attenuating material such as tissue, the amplitude of the wave decreases with distance. This attenuation is due to either absorption or scattering. Absorption is a mechanism that represents that portion of ultrasonic wave that is converted into heat, and scattering can be thought of as that portion of the wave, which changes direction. Because the medium can absorb energy to produce heat, a temperature rise may occur as long as the rate of heat production is greater than the rate of heat removal. Current interest with thermally mediated ultrasound-induced bioeffects has focused on the thermal isoeffect concept. The non-thermal mechanism that has received the most attention is acoustically generated cavitation wherein ultrasonic energy by cavitation bubbles is concentrated. Acoustic cavitation, in a broad sense, refers to ultrasonically induced bubble activity occurring in a biological material that contains pre-existing gaseous inclusions. Cavitation-related mechanisms include radiation force, microstreaming, shock waves, free radicals, microjets and strain. It is more challenging to deduce the causes of mechanical effects in tissues that do not contain gas bodies. These ultrasonic biophysics mechanisms will be discussed in the context of diagnostic ultrasound exposure risk concerns.

Biophysical Phenomena↗
PubMed1985

Computer-assisted assessment of the fetal biophysical profile.

The biophysical profile assesses fetal heart rate, breathing movements, fetal body movements, amniotic fluid volume, and fetal tone. In the past, these data have been scored by an arbitrary, unweighted system. While this approach is useful in detecting major anomalies and oligohydramnios, both static observations, the dynamic variables (fetal heart rate, fetal breathing movements, and fetal body movements) have added little information beyond that of an extended nonstress test alone. We have evaluated an alternative biophysical assessment system, modeled after extended physiologic studies, which not only acquires dynamic fetal variables simultaneously but, with computer assistance, quantifies the biophysical information. With an ADR 4000/L scanner, a Hewlett-Packard 8040 A monitor, and a specially programmed IBM microcomputer, we studied 100 normal term fetuses during 60-minute epochs. Each gestation had normal amniotic fluid volume and fetal tone. Normative values for the dynamic variables, expressed as means +/- SD were: fetal heart rate, 137 +/- 6.3 bpm; incidence of fetal breathing movements, 25.0% +/- 17.3%; rate of fetal breathing movements, 46.0 +/- 9.4 breaths/min; total fetal breathing movements, 823 +/- 61; incidence of fetal body movements, 8.5% +/- 3.9%; accelerations (greater than 15 bpm, 15 seconds), 14.1 +/- 6.3. We conclude that this approach is practicable, respects the biologic cycles of fetal behavior, and provides a basis for population standards and sequential study of the same fetus.

Amniotic Fluid↗
PubMed1996

The modified biophysical profile: antepartum testing in the 1990s.

OBJECTIVE: Our goal was to determine the false-negative and false-positive rates of antepartum testing by use of the modified biophysical profile. STUDY DESIGN: From Jan. 1, 1990, through Dec. 31, 1994, antepartum testing results were gathered prospectively and tabulated monthly. For 1 year, 1991, detailed intrapartum and neonatal data were collected from all women admitted and delivered as a result of an abnormal antepartum test result. RESULTS: The false-negative rate of the antepartum testing protocol was 0.8 per 1000 women tested. Sixty percent of those delivered because of an abnormal antepartum test had no evidence of short-term or long-term fetal compromise. False-positive test results led to preterm delivery in 1.5% of those tested before term. CONCLUSION: The false-negative rate of the modified biophysical profile is lower than that of the nonstress test and compares favorably with the false-negative rates of the contraction stress test and the complete biophysical profile. Iatrogenic prematurity resulting from intervention for false positive test results occurred in 1.5% of women tested before 37 weeks.

Adult↗
PubMed1999

Ocular explosions from periocular anesthetic injections: a clinical, histopathologic, experimental, and biophysical study.

OBJECTIVES: An increasing number of cases are being recognized in which a periocular anesthetic for cataract surgery has been inadvertently injected directly into the globe under high pressure until the globe ruptures or "explodes." The objectives of the current study were to (1) analyze this injury clinically and histopathologically through a series of seven case reports; (2) reproduce the injury experimentally in human eyebank eyes, live anesthetized rabbit eyes, and human cadaveric eyes; (3) investigate the biophysical basis of the injury; and (4) outline recommendations to help decrease the risk of ocular rupture with periocular injections. DESIGNS/PARTICIPANTS: Clinical, histopathologic, experimental animal, autopsy eye, and theoretical biophysical study. METHODS: The clinical and histopathologic findings of the patients' eyes were documented. Human eyebank eyes, live anesthetized rabbit eyes, and human cadaveric eyes were exploded via direct intraocular saline injection. The laws of Bernoulli, LaPlace, Friedenwald, and Pascal were used to investigate theoretically the biophysics of the injury. RESULTS: The findings of anterior and posterior scleral rupture, retinal detachment, vitreous hemorrhage, and lens extrusion were observed clinically and experimentally. In some clinical and experimental cases, the anterior segment appeared entirely normal despite a posterior rupture. The surgeon proceeded with and completed the cataract surgery in two of the seven clinical cases without knowledge of the rupture. The pressure required to produce such an injury is in the range of 2800 to 6400 mmHg, and this pressure is more easily attained with a 3-ml syringe than with a 12-ml syringe. CONCLUSIONS: Explosion of an eyeball during the injection of anesthesia for ocular surgery is a devastating injury that may go unrecognized. The probability of an ocular explosion can be minimized by (1) the use of a blunt needle and a 12-ml syringe, (2) aspirating the plunger and wiggling the syringe before injection, (3) discontinuing the injection if corneal edema or resistance to injection is noted, and (4) inspecting the globe for evidence of intraocular injection before ocular massage or placement of a Honan balloon. On recognition of an ocular explosion, immediate referral to and intervention by a vitreoretinal surgeon is optimal.

Aged↗